Space telegraphy.



No. 767,982.- PATENTED AUG. 16, .1904.

J. S. STONE.

SPACE TELEGRAPHY.

APPLICATION FILED NOV. 25, 1903. no MODEL.

WPTNEESEE= w 7 m 'p maa v y- H I No. 767.982.

UNITED STATES Patented August 16, 1904.

PATENT OFFICE.

JOHN STONE STONE, OF CAMBRIDGE, MASSACHUSETTS, ASSIGNOR TO WILLIAM W.SWAN, TRUSTEE, OF BROOKLINE, MASSACHUSETTS.

SPACE TELEGRAPHY- SPECIFICATION forming part of Letters Patent No.767,982, dated August 16, 1904.

Application filed November 25,1903. Serial No. 182,629. (No model.

To all whom it may concern: Be it known that I, JOHN STONE STONE, acitizen of the United States, and a resident of Cambridge, in the countyof Middlesex and State of Massachusetts, have invented a certain new anduseful Improvement in Space Telegraphy, of which the following is aspecification. This invention relates to wireless or space telegraphy inwhich signals are transmitted in the form of electroradiant energywithout connecting wires between the transmitting and receivingstations; and it more particularly relates to selective and multiplexspace telegraph systems in which the signals to be selectively orseparately received are trans-.v mitted by means of electromagneticwaves,

which may all be of the same frequencyor time of vibration, but whichare differentiated from one another by the number of groups or trains ofwaves transmitted per unit of time.

Thus by means of the system-herein describedit is possible toselectively receive the energy of electromagnetic signal-waves not onlyof a predetermined frequency or time of vibration to the exclusion ofwaves of other frequencies, but also of a predetermined group orwave-train frequency to the exclusion of waves of other group orwave-train frequencies.

In wireless or space signaling in which signals are transmitted byelectromagnetic waves in the form of radiant energy the frequency ofsaid Waves is usually of the order one million periods per second; butthese Waves are transmitted in groups or trains, each group or trainresulting from the disruptive discharge of a condenser across aspark-gap. The number of these disruptive discharges per unit of timedetermines what I have herein termed the group frequency or thewave-train frequency, which may be two hundred, three hundred, fivehundred, &c., per second, as distinguished from the electrical frequencyof the electromagnetic waves making up these groups, which frequency, asbefore stated, is usually of the order of one million periods per secondand is equal to the ratio of the speed of light to the wave length ofthe transmitted wave.

. Systems in which signals transmitted by electromagnetic waves of onegroup frequency are selectively received to the exclusion of signalstransmitted by electromagnetic waves of other group frequencies arewell-known in the I art of space telegraphy to-day, having beendescribed in United States Letters Patent No. 660,155, granted October23, 1900, to B. A. Fiske on an application filed, September 7,

.1898. In this patent is described a self-restoring coherer seriallyconnected with a magnet having its armature attuned to respond to adefinite frequency in the manner well known in the system of reed orharmonic telegraphy developed by Gray and others, and in the Britishpatent to A. E. Blondel, No. 21,909 of 1900, is described-aself-restoring coherer serially connected with a monotelephone or atelephone whose diaphragm is attuned to re-v spond to a definitefrequency in the manner Well'known in the system of harmonic telegraphydeveloped by Mercadier. In the invention herein described either one ofthese mechanically-attuned receiving instruments may to which themonotelephone is mechanically attuned; but the system herein describeddoes not depend solely upon such attuning of the elevated conductor norsolely upon such attuning of the local coherer-circuit. y

In the system herein described a receiving system provided with meansmechanicallyattuned to respond only to signals transmitted byelectromagnetic waves of a predetermined and predetermined period ofvibration.

group or wave-train frequency is combined with a closed resonant circuitattuned to respond to electromagnetic waves of one predeterminedelectrical frequency to the exclusion of waves of different electricalfrequencies.

A system electrically attuned to respond to electromagnetic waves of onefrequency to the exclusion of electromagnetic waves of differentfrequency I have described in my Letters Patent Nos. 71 L756 and 71L831, to which reference may be had for a more complete disclosure ofthe principles involved than is necessary to herein set forth.

In the drawings which accompany and form a part of this specification,Figure 1 illustrates in diagram a transmitting system adapted to developsimple harmonic electromagnetic waves of a definite frequency or time ofvibration and also of a constant group or wave- I train frequency. Figs.2 and 3 illustrate in diagram receiving systems embodying two forms ofmy invention.

In the figures, V V represent elevated conductors. M M are transformers.C C C arecondensers. LLL areinductances. L L? are choking-coils. D D areself-restoring wave-detectorsor electric translating devices. B B arebatteries. R is an electromagnet. 9 is a reed mounted on the standard P.T T are signal-indicating devices. I I are impedances.

The resonant circuits M L D C, M L M C, and M L D C are each attuned tothe frequency of the electromagnetic Waves by which the signals to bereceived are transmitted, and as set forth in my Letters Patent above.referred to currents of much greater amplitude or strength aredeveloped in each circuit by waves of said frequency than by waves ofany other frequency.

In Fig. 2 is shown any one of the well-known self-restoringwave-detectors or electric translating devices D connected in serieswith the resonant circuit M CL, and in Fig. 3 is shown a wave-detectoror electric translating device D which utilizes in its operation thedissipated energy of the currents developed in the resonant circuit ofwhich it forms a part such, for example, as the fine wire or strip of abolometer described in my applications, Serial Nos. 119,211 and 182,628.In series with the translating device D is an electromagnet R, which isprovided with an armature or reed a", formed of a thin strip of steelsupported at one end or otherwise, so as to have a definite If desired,this reed may be formed of non-magnetic metal and provided at itsextremity with an armature of soft iron; This armature '2' when itsamplitude of vibration is sufficient for 'the purpose closes the circuitof battery B of the signal-indicating device T, which may be atelephone, and for this purpose the armature T and its cooperatingcontact-point may be provided with carbon contacts.

In Fig. 3 the indicating device is a. monotelephone or a telephone T,having a diaphragm adapted to respond more strongly to currentvibrations of one frequency than to current vibrations of otherfrequencies. Such telephones are well known and require no descriptionhere.

The resonant circuits associated with the elevated conductor V absorbsuflicient energy to operate the wave-detectors D1) only when theelectromagnetic waves received by the elevated conductor are of thefrequency to which the resonant circuits are attuned. \Vhen waves of thefrequency to which the resonant circuits are attuned are received by theelevated conductor, electrical oscillations of corresponding frequencyare developed in the resonant circuits, and as the wave-detectors D Dare self-restoring pulsations of batterycurrent are set up in the localcircuits 1) (7 R L1 or D B T. The frequency of these pulsations ofbattery-current correspond to the number of groups or trains of waves,or to what I have hereinbeforc referred to as the group frequency orwave-train frequency. Consequently if the reed or armature 7' or 'r ismechanically attuned to vibrate in this frequency it will executevibrations of greater amplitude than it would execute were thepulsations of battery-current of a, different frequency. In other words,if the waves are transmitted with a group frequency different from thatto which the receiver is attuned the reed will either not respond orelse its amplitude of vibration will be insufficient to close thecircuit of the indicating deviceT or to produce an appreciable notewhere the signal-indicating device T is not employed, even if thefrequency of the electromagnetic waves be that to which the resonantcircuit is attuned. An acoustic resonator G, attuned to the period ofthe reed 1', may be employed.

In place of the magnet R and reed I may connect in the local circuit aline wire of magnetic material under such tension so as to have anatural period of vibration corresponding to the period of thepulsations of batterycurrent. The reaction of the magnetic lield set uparound this wire on the field of a powerful permanent magnet surroumlingthe wires will cause the latter ,to execute vibrations of appreciableamplitude when the pulsations of battery -current flowing therethroughcorrespond in frequency to the frequency to which this wire ismechanically attuned. This wire may actuate a microphonic relay in themanner described by (lauro in LEcZai rm e Elect/MW, Vol. 19, May 27,1899, page 301. As a substitute for the magnet lt and reed r I may alsouse the microtelephonic relay described in British Patent No. 9,712,series of 1898, granted to Oliver Lodge, or the modification thereofdescribed by Shaw in the Proceedings 0f 6/: Phys/cut in the groupfrequency corresponding to-the Society 0 f London, Vol, XVII, page 317,London, 1901. i

In Fig. 3, a is a flat movable armature such as described in my LettersPatent No. 7 37 170, August 25, 1903, having its plane at an angle offorty-five degrees with the axis ofthe coil L. The suspension of thisarmature is ten: sioned, so as to have a torsional period equal to theperiod of the group or wave-train fre quency. The operation of thisarmature is more fullyflescribed in said patent.

By thus combining the old and well-known systems of tuning mechanicallyto group free 1 quency with the selective receiving systems of myhereinbefore-mentioned Letters Patent a greater security frominterference from out 1 side sources may be effected, because theindication of a signal by the system herein described depends uponthecooperation of an accurately attuned mechanical system with anaccurately-attunedelectricalsystem. Further.- more, by providing eachone of a number of adjacent receivingsystems with a differentlyattunedreed a corresponding. number of separate signals, may be simultaneouslytransmitted by means of electromagnetic waves of a single frequencyradiated from the same or from different stations, each provided withmeans for causing the emission of these Waves taining constant speed,and therefore the fre-:

quency of the currents produced-by said generator is constant- The groupor wave-train; frequency@'. a, the number of times per second thatthe-condenser C is charged and dis, charged across the spark-gapis equalnumerically to twice the frequency of the currents developed by thegenerator.

A condenser C of the proper capacity, connected in series with theprimary of transformer M, is of material assistance in maintaining theload of the generator, and hence the frequency of the currents developedby the generator more constant.

I claim 1. In a system for receiving the energy of: electromagneticsignal-waves of onefrequency to the exclusion of the energy of likewaves of different frequency, an elevated conductor, an

electrictranslating device, and aresonant circuit or group of resonantcircuits, interposed between said elevated conductor and said elsetrictranslating device, said resonant circuits being attuned to thefrequency of the waves the energy ofwhich is to be received, incombination with a local circuit including in series said electrictranslating device and an electromagnetic device provided with meansmechanically attuned to respond to the group or wave-train frequency ofsaid electromagnetic signal-waves and a source of electrical energyassociated with said local circuit, substantially as described.

2. In a system of space telegraphy, an elevated conductor,aself-restoring wav'e detcc' tor-or receiver, and a resonantcircuit0peratively connected-with said elevated conductor and saidself-restoring wave-detector or receiver, said resonant circuit beingattuned to the frequency of the wavesthe energy of which is to bereceived, in combination with a circuit including'in series saidself-restoring wave-detector or receiver and an electromagnetic deviceprovided with means mechanically attuned to respond to the grouporwavetrain-frequency of said waves, and means in said circuitforattuningthe circuit to the said group or wave-train frequency. I i

In a system of space telegraphy, an ole.- vated conductor, a circuitattuned by=capacity and inductance to be more responsive toelectromagnetic waves of one frequency than to ielectromagnetlc'waves ofother frequencies,

associated with, said elevated conductor,-a

nected with said circuit, and a signal-indicating device, mechanicallyattuned to respondto the group or wave-train frequency of saidelectromagnetlc waves, operatively connected with said wave-detector. I

4:. Ina system of space telegraphy, anelevated conductor, a circuitattuned by capacity and inductance tobe moreresponsive toelectromagnetic waves of one frequency than to electromagnetic waves ofother frequencies, associated with said elevated conductor, aself-restoring wave-detector operatively connected with said circuit anda signal-indicating device, mechanically attuned to respond ;to thegroupor' wave-train frequency of said electromagnetlc waves, operativelyconnected with said wave-detector, in combination with a system adaptedto transmit electromagnetic waves of the frequency to whichself-restoring wave-detector, operatively consaid circuit is attuned andof the group or wave-train frequency to which said signal-in dicatingdevice is mechanically attuned 5. In asystem of space telegraphy, areceiver or wave-detector, asignal-indijcating device, means connected inshunt to the terminals ofthe receiver or Wave-detector and to theterminalsof the signal indicating device forimpressing aunidirectionaldifference of potential thereon,v andnmeans whereby theaforesaid difference of potential may be varied by electromagneticsignal-waves.

a second circuit, containing a source of electric energy and animpedance,' connected 1n shunt to the first-mentioned circuit.

8. In a system of space-telegraphy, a cireuit, attuned by a coil and acondenser to a given group or wave-train frequency and containing areceiver or wave-detector and a signal-indicating device connected inseries, said signal indicating device being attuned mechanically to saidgiven group or wave-train frequency.

9. In a system of space telegraphy, a circuit, including a receiver orwave-detector and attuned to a predetermined group or wavetrainfrequency by means of a coil and a condenser connected in series.

10. In a system of space telegraphy, a circuit, resonant to thefrequency of the electromagnetic waves the energy of which is to bereceived, in combination with a circuit resonant to the group orwave-train frequency of said waves.

11. In a system of space telegraphy, a circuit, resonant to thefrequency of the electromagnetic waves, the energy of which is to bereceived, in comblnation with a elrcuit resonant to the group orwave-tram frequency of said waves, and a signal-indicating devicemechanically attuned to said group or Wavetrain frequency operativelyconnected with the last-mentioned circuit.

12. In a system of space telegraphy, an elevated conductor, a closedcircuit associated therewith and attuned to the frequency of the wavesthe energy of which is to be received,

a self-restoring wave-detector operatively connected with said e1rcu1t,a second circuit connected with said wave-detector and at tuned to thegroup or wave-train'frequency of said waves and a signal-indicatingdevice, mechanically attuned to said group or wavetrain frequency,connected with the last-mentioned circuit.

13. In a system of space telegr-aphy, means for receiving the energy ofelectromagnetic signal-waves of one frequency to the exclusion of theenergy of like waves of different frequency, in combination with acircuit attuned to a given group or wave-train frequency and containinga receiver or waVedetector and a signal-indicating device connected inseries, said signal-indicating device being attuned mechanically to saidgroup or wave-train frequency.

1 1. Inasystem of space telegraphy, means for receiving the energy ofelectromagnetic signal-waves of one frequency to the exclusion of theenergy of like waves of diii'erent frequency, in combination with acircuit including a receiver or wave-detector and attuned to apredetern'iined group or wave-train frequency by means of a condenserand a coil.

15. In a system of space telegraphy, a circuit resonant to the frequencyof the waves the energy of which is to be received in combination withan electromagnetic device mechanically attuned to the group orwave-train frequency of said waves.

16. In a system of space telegraphy, means for receiving the energy ofelectromagnetic signal-waves of one frequency to the exclusion of theenergy of like waves of different frequency, in combination with anelectromagnetic device mechanically attuned to the group or wave-trainfrequency of said waves.

17. In a system of space telegraphy, an elevated receiving-conductor, aresonant circuit associated therewith and attuned to the frequency ofthe waves the energy of which is to be received, an electroreceptivedevice adapted to utilize in its operation the dissipative energy of theelectrical oscillationsdeveloped in said resonant circuit, and asignalindicating device mechanically attuned to the group or wave-trainfrequency of said waves operatively connected with saidelectroreceptivev device.

18. In a system of space telegraphy, an elevated receiving-conductor, aresonant circuit, attuned to the frequency of the waves the energy ofwhich is to be received, an electrorcceptive device adapted to utilizein its operationthe dissipative energy of the electrical oscillationsdeveloped in said resonant circuit, a signal-indicating device,mechanically attuned to the group or wave-train frequency of said waves,operatively connected with said electroreceptive device, and a resonantcircuit or a group of resonant circuits attuned to the same frequency asthe first-mentioned resonant circuit and interposed between the elevatedconductor and said first-mentioned resonant circuit.

19. In a system of space telegraphy, an elevated transmitting-conductor,a sonorous circuit associated therewith, an alternating-currentgenerator, a transformer associating said alternating-current generatorwith said sonorous circuit, and a condenser connected across theterminals of the primary winding of said transformer.

20. In a space-telegraph receiving system, an electromagnet having anarmature attuned mechanically to the group or wave-train frequency ofthe waves to be received, a local cir- IO containing a telephone orother signal-indieating device and adapted to be closed by saidarmature,- and a microphonic contact through which said circuit may beclosed by said armature.

22. In a space-telegraph receiving system,

means for indicating signals comprising anelectromagnet having anarmature attuned mechanically to the group, or wave train frequency ofthe electromagnetlc s1 gnal-waves to 20 be received and operativelyconnected with an acoustic resonator attuned to said frequency.

23. In a space-telegraph receiving system, a signal-indicating device,mechanically attuned to the group or wave-train frequency onator,

of the electromagnetic signal-waves to be received, in combination withan acoustic res- 24. In a system of space telegraphy, a resonant circuitattuned to the frequency of the Waves the energy of which is to bereceived, an elevated conductor associated with said resonant circuit, aself-restoring electroreceptive device associated with said resonantcircurt, a local c1rcu1t assoclated with said electroreceptivedevice andattuned to the group or Wave-train frequencyof sald waves by a condenserand an 1nductance corl andia slgnal-indicating device associatedwithsaid Ideal circuit and attuned mechanically to said group orwave-train frequency.

, In testimony whereof I have hereunto sub-4 scribed my name this 24thday of November, 1903.

' JOHN STONE STONE.

Witnesses:

G. A. HIGGINS, BRAINERD T. J UDKINS.

